The board-to-board connector for connecting electronic circuits on two opposed printed circuit boards to each other is used as a connector used in electronic devices such as mobile phones and digital cameras which have been reduced in size and weight. In the board-to-board connector, one of the connected printed circuit board has a socket and the other of the connected printed circuit board has a header. By connecting the socket to the header, electronic circuits formed on both the printed circuit boards are connected to each other.
In this type of conventional board-to-board connector, as disclosed in, for example, Unexamined Patent Publication No. 2004-055464, a contact obtained by bending a strip conductor in the shape of a dead end is provided at the socket as one connector, and a post having a conductor protruding from the header as the other connector is inserted into and engaged with the dead end portion of the contact, thereby bringing the inner side surface of the dead end portion of the contact into spring contact with the outer side surface of the post for electrical connection.
However, from the perspective of further reduction in size and thickness, since the connector disclosed in the above-mentioned Patent document 1 has the structure that the inner side surface of the dead end portion of the contact is brought into contact with the outer side surface of the post for electrical connection, when one attempts to make the structure thinner, bending of the contact becomes difficult. In addition, when the contact portion is shortened, sufficient contact area is hard to be ensured and binding strength between the contact and the post due to engagement is decreased. Thus, disadvantageously, the engagement is easy to be released.
For narrower pitch and higher density, it is necessary to narrow the pitch of the contact and the post which are fixed to a housing of the connector as well as their press-fit grooves. However, since the housing, into where the contact and the post are press-fit, is made of synthetic resin, there is a limitation in reducing the size of the housing due to workability and strength, making it more difficult to reduce the pitch. Furthermore, since minimum thickness of the housing is needed to stand press-fitting of the contact and the post, it is difficult to reduce the height of the connector.
As described above, the conventional board-to-board connector is formed of moldings and metallic components and both electronic and mechanical connection is performed by elastically deforming mechanically-processed metallic springs having complicated and three-dimensional structure. Thus, obviously, there is a limitation in lower height (thinner size) and higher density.